Avoid retaining a reference to ActivityIconLoader in its OnIconReady()

components/arc/intent_helper/activity_icon_loader.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_
 #define COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 83 matching lines @@
  private:
   friend class base::RefCounted<ActivityIconLoader>;
   ~ActivityIconLoader();
 
   // A function called when the mojo IPC returns.
   void OnIconsReady(std::unique_ptr<ActivityToIconsMap> cached_result,
                     const OnIconsReadyCallback& cb,
                     std::vector<mojom::ActivityIconPtr> icons);
 
   // Resizes and encodes |icons| and returns the results as ActivityToIconsMap.
-  std::unique_ptr<ActivityToIconsMap> ResizeAndEncodeIcons(
+  static std::unique_ptr<ActivityToIconsMap> ResizeAndEncodeIcons(
       std::vector<mojom::ActivityIconPtr> icons);
 
   // A function called when ResizeIcons finishes. Append items in |result| to
   // |cached_icons_|.
   void OnIconsResized(std::unique_ptr<ActivityToIconsMap> cached_result,
                       const OnIconsReadyCallback& cb,
                       std::unique_ptr<ActivityToIconsMap> result);
 
   // The maximum scale factor the current platform supports.
   const ui::ScaleFactor scale_factor_;
   // A map which holds icons in a scale-factor independent form (gfx::Image).
   ActivityToIconsMap cached_icons_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ActivityIconLoader);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_